This happens because the site uses the older "http" web protocol that is not "secure". The web is moving to "https" and new versions of the popular web browsers are now starting to warn you of every site that still uses the old protocol.

This certainly does not mean there are viruses here though! The old protocol transmits information as plain text over the internet, which makes it easier for a bad guy to see everything that passes between your computer and the forum servers. The new protocol encrypts everything, so a bad guy cannot just read what you are sending/receiving.

Should you care? I wouldn't worry a lot about this just yet, but you are going to continue getting warnings from sites that use the old protocol. Many of the older forum websites have been reluctant to move to the new protocol, and some web hosting companies will charge more to use it. I think there are only two areas of possible concern on a site like this. One would be that someone might intercept your private messages. More of a problem would be that someone might harvest user names and passwords more easily from an insecure website.

IMO, the main takeaway should be DO NOT USE THE SAME PASSWORD HERE THAT YOU USE ON OTHER SITES. Probably not a big deal if someone hacks your Gibson Forum account. But if you use the same password, they (theoreticlaly) might be able to hack your credit card or bank accounts.